US20050081910A1 - High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers - Google Patents
High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers Download PDFInfo
- Publication number
- US20050081910A1 US20050081910A1 US10/922,420 US92242004A US2005081910A1 US 20050081910 A1 US20050081910 A1 US 20050081910A1 US 92242004 A US92242004 A US 92242004A US 2005081910 A1 US2005081910 A1 US 2005081910A1
- Authority
- US
- United States
- Prior art keywords
- cell
- algaas
- solar energy
- electrical power
- providing electrical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000000872 buffer Substances 0.000 title claims description 59
- 229910052710 silicon Inorganic materials 0.000 title claims description 27
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims description 19
- 239000010703 silicon Substances 0.000 title claims description 19
- 239000000758 substrate Substances 0.000 title description 19
- 229910052732 germanium Inorganic materials 0.000 title description 12
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 title description 5
- 229910000980 Aluminium gallium arsenide Inorganic materials 0.000 claims abstract description 108
- 229910000577 Silicon-germanium Inorganic materials 0.000 claims description 29
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 2
- 229910052782 aluminium Inorganic materials 0.000 claims 2
- 101000981884 Brevibacillus parabrevis Valine racemase [ATP-hydrolyzing] Proteins 0.000 claims 1
- 239000000463 material Substances 0.000 description 25
- 239000000203 mixture Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 238000001228 spectrum Methods 0.000 description 7
- 238000000137 annealing Methods 0.000 description 6
- 230000005611 electricity Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- 238000000038 ultrahigh vacuum chemical vapour deposition Methods 0.000 description 5
- 239000000969 carrier Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 229910016920 AlzGa1−z Inorganic materials 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000004050 hot filament vapor deposition Methods 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
- H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
- H01L31/0687—Multiple junction or tandem solar cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/544—Solar cells from Group III-V materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/547—Monocrystalline silicon PV cells
Definitions
- the invention relates to the field of solar cells, and in particular to tandem solar cells.
- Photovoltaic cells are devices that convert light energy into electric energy. Solar cells provide a number of distinct advantages when compared to conventional energy sources. For example, solar cells produce electricity without any harmful emissions and do not rely on finite fossil fuel supplies. Furthermore, solar cells create electric power without any active supply of fuel and thus can serve as sources of electric power in remote terrestrial locations as well as in space.
- tandem solar cells One of the most promising technologies for realizing solar cells with higher efficiency and lower cost relative to silicon solar cells is that of tandem solar cells.
- U.S. Pat. Nos. 6,340,788 and 5,009,719 as well as U.S. Published Patent Applications Nos. 2004/0079408 and 2002/0179142 disclose tandem solar cells.
- a tandem solar cell multiple solar cells consisting of different materials are stacked upon each other.
- a solar cell In order for electricity to be produced from light, a solar cell must be able to perform two primary functions: 1) it must be able to absorb the incident sunlight to produce free electronic carriers and 2) it must be able to collect these carriers to produce electric power.
- the ability of a solar cell to absorb sunlight is determined by an intrinsic materials property called the bandgap energy.
- tandem solar cell in order to absorb sunlight as efficiently as possible a tandem solar cell must consist of a stack of multiple photovoltaic cells consisting of a highest bandgap material on the side upon which light is incident, with many successive layers beneath it having progressively lower bandgaps.
- Such a structure results in two advantages: 1) a larger portion of the sunlight spectrum is absorbed and 2) more of the sunlight absorbed is absorbed at energies close to the bandgap energies of the cells of which the tandem cell consists, resulting in higher efficiencies within each individual cell, and thus higher efficiency for the tandem cell.
- tandem solar cell device current is dictated by the lowest current present in any of the Individual sub-cells within the tandem solar cell. Accordingly, current-matching between all sub-cells is ideal and puts a further constraint on the bandgaps that the materials of the sub-cells must have in order for a tandem cell to exhibit high efficiency. Effectively, the materials must be selected to apportion the absorption and collection of free charge carriers from sunlight evenly, which requires the sub-cells to have very specific sets of bandgap energy values for optimum efficiency.
- the maximum efficiency of a current-matched tandem solar cell generally increases with the number of sub-cells, and accordingly a larger number of current-matched sub-cells is preferable to a smaller number with regard to maximizing tandem solar cell device efficiency.
- solar cells must not only absorb sunlight, but also must collect the light-generated free electronic carriers that are generated, in order to produce electric power.
- the solar cell materials must be of as high crystalline perfection as possible.
- all the different solar cell materials within one tandem cell have had to have identical crystalline structures with the same lattice constant in order for high-quality tandem cells with high efficiency to be produced. Materials systems with this property are called lattice-matched.
- lattice-mismatched materials systems typically have low solar cell efficiency performance.
- a solution to the current solar cell cost problem would be to merge the high-efficiency of tandem solar cells with the low-cost of silicon substrate-based solar cells.
- An ideal embodiment would include a high-efficiency tandem solar cell consisting of as many current-matched, high crystalline quality sub-cells as possible integrated onto an inexpensive silicon substrate which is used as a growth substrate and an active tandem cell sub-cell.
- a critical problem is that there exist no common materials that are lattice-matched to silicon that can provide the bandgap values required for the necessary absorption over the whole solar spectrum, along with tandem cell sub-cell current matching. Accordingly, attempts to date to make tandem solar cells on silicon substrates have resulted in high threading dislocation density ( ⁇ 10 9 dislocation/cm 2 ) and poor crystalline quality; and thus accordingly have poor solar energy conversion efficiency.
- the latter method has involved growing relatively high quality ( ⁇ 10 6 dislocations/cm 2 ) GaInP 2 /GaAs/Ge three sub-cell tandem solar cells on silicon substrates using thick ( ⁇ 10 ⁇ m) layers of SiGe, grading from pure Si at the silicon substrate, through a number of layers of SiGe of increasing Ge concentration up to pure Ge, and by then growing GaAs and GaInP 2 lattice-matched to the Ge layer.
- This method however, has the disadvantage that due to the thick SiGe buffer, it is not possible to integrate the buffer or any layers beneath it into the active tandem cell structure.
- a system for providing electrical power responsive to solar energy.
- the system includes a Si cell, an AlGaAs cell, and a Ge cell.
- the Si cell is for providing electrical power responsive to solar energy within a first frequency range.
- the AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range.
- the Ge cell is coupled to a second side of the Si cell, and the Ge cell provides electrical power responsive to solar energy within a third frequency range.
- the system includes a Si cell, a first AlGaAs cell, a second AlGaAs cell, and a Ge cell.
- the Si cell is for providing electrical power responsive to solar energy within a first frequency range.
- the first AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range.
- the second AlGaAs cell is coupled to the first AlGaAs cell, and is for providing electrical power responsive to solar energy within a third frequency range.
- the Ge cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to solar energy within a fourth frequency range.
- the system includes a Si cell, an AlGaAs cell and a Ge buffer layer.
- the Si cell is for providing electrical power responsive to solar energy within a first frequency range.
- the AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range.
- the Ge buffer layer is less than about 60 nm in thickness and is positioned between the Si cell and the AlGaAs cell.
- the system includes a Si cell, first and second AlGaAs cells and a first SiGe cell.
- the Si cell is for providing electrical power responsive to solar energy within a first frequency range.
- the first AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to a solar energy within a second frequency range.
- the second AlGaAs cell is coupled to the first AlGaAs cell, and is for providing electrical power responsive to a solar energy within a third frequency range.
- the first SiGe cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to a solar energy within a fourth frequency range.
- FIG. 1 shows an illustrative diagrammatic side view of a photovoltaic device in accordance with an embodiment of the invention
- FIG. 2 shows an illustrative diagrammatic flowchart of a method of forming the device shown in FIG. 1 ;
- FIG. 3 shows an illustrative graphical view of total collected photocurrent under the AM1.5 solar spectrum versus wavelength for a device as shown in FIG. 1 ;
- FIG. 4 shows an illustrative diagrammatic view of an energy diagram for a device as shown in FIG. 1 ;
- FIG. 5 shows an illustrative diagrammatic side view of a photovoltaic device in accordance with another embodiment of the invention.
- tandem cell structures based upon silicon substrates may be formed in accordance with various embodiments of the invention.
- the materials Ge, AlAs, GaAs, Al x Ga 1-x As (consisting of all compositions intermediate between AlAs (2.67 eV(direct)) and GaAs (1.42 eV)), and GaInP 2 are all lattice-matched and offer a wide variety of bandgap values.
- a four sub-cell tandem cell based upon Ge on the backside and two AlGaAs top cells of different compositions on the front-side may be optimized if a material having a bandgap of ⁇ 1.0 eV is placed between the Ge and the AlGaAs layers.
- silicon's bandgap of 1.12 eV is very well suited for this layer.
- the use of a high-quality ultra-thin Ge growth buffer on each side of a silicon wafer allows for the high-quality growth of both Ge and all compositions of AlGaAs on Si.
- the added fact that such a thin Ge buffer is sufficient for high-quality Ge and AlGaAs growth on Si greatly minimizes the parasitic absorption that inevitably occurs in low bandgap growth buffers and makes this cell structure highly promising for a highly-efficient, low-cost tandem solar cell technology.
- Such high quality germanium layers may be grown directly on silicon by use of an ultra high vacuum chemical vapor deposition (UHV-CVD) low temperature germanium buffer layer deposition followed by thermal cyclic annealing.
- UHV-CVD ultra high vacuum chemical vapor deposition
- An object of this invention is to provide high-efficiency tandem solar cells on low-cost silicon substrates. This is achieved, in part, through the use of ultra-thin high-quality Ge growth buffer layers grown by ultra high vacuum chemical vapor deposition.
- the system includes a Si substrate-based cell, a grown AlGaAs cell, and a grown Ge cell.
- the grown AlGaAs cell is coupled to a first side of the Si cell, the side upon which light is incident, and is for providing electrical power responsive to high energy solar energy.
- the Si substrate-based cell is for providing electrical power responsive to solar energy at intermediate energies.
- the grown Ge cell is coupled to a second side of the Si cell, and the Ge cell provides electrical power responsive to solar energy at low energies.
- the exact composition of the AlGaAs sub-cell material is of such a composition as to provide current matching with the Si and Ge sub-cells and is dependent upon the exact thickness of each sub-cell.
- the system includes a Si cell, a first Al y Ga 1-y As cell, a second Al x Ga 1-x As cell, and a Ge cell.
- the bandgap of the second Al x Ga 1-x As cell is larger than that of the first Al y Ga 1-y As cell in this embodiment, requiring that 1>x>y>0.
- the first Al y Ga 1-y As cell is coupled to a first side of the Si cell, the side upon which light is made incident.
- the second Al x Ga 1-y As cell is coupled on the side of the first Al y Ga 1-y As opposite the Si substrate.
- the Ge cell is coupled to the second side of the Si substrate-based cell.
- the second Al x Ga 1-x As cell is for providing electric power responsive to solar energy of high energy.
- the first Al y Ga 1-y As cell is for providing electric power responsive to solar energy of slightly lower energy.
- the Si substrate-based cell is for providing electric power responsive to solar energy of even lower energy.
- the Ge cell is for providing electric power responsive
- the system includes a Si cell, first and second AlGaAs cells and a first SiGe cell.
- the Si cell is for providing electrical power responsive to solar energy within a first frequency range.
- the first Al y Ga 1-y As cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range.
- the second Al x Ga 1-x As cell is coupled to the first Al y Ga 1-y As cell, and is for providing electrical power responsive to solar energy within a third frequency range.
- the first SiGe cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to solar energy within a fourth frequency range.
- a high bandgap AlGaAs layer may be provided on the top surface of the device for surface passivation to make the surface electrically inactive.
- a photovoltaic device 10 in accordance with an embodiment of the invention includes a first cell 12 formed of Al x Ga 1-x As, and a second cell 14 formed of Al y Ga 1-y As that are coupled to one another via an AlGaAs tunnel junction 16 .
- the device 10 also includes a Si cell 18 that is coupled to the Al y Ga 1-y As cell 14 via an ultra thin Ge buffer layer 20 .
- Another ultra thin Ge buffer layer 22 is formed on the backside of the Si cell 18 , and a Ge cell 24 is formed on the Ge buffer layer 22 .
- Electrical conductors 26 and 28 are applied to the top and bottom of the device 10 for connecting to power output terminals 30 and 32 respectively.
- the cells 12 , 14 , 18 and 24 are each designed to provide photovoltaic responses over different solar energy ranges, and the thickness and bandgap energy of each sub-cell determines the current that will be produced by the overall cell.
- Each cell therefore, may be designed to have a thickness and bandgap energy such that the current produced by each cell is equal to the current produced by each of the other cells, providing that that current output of the device is maximized.
- the power provided by the device is proportional to to the sum of the open-circuit voltages of each cell multiplied by the current provided by the minimum current produced by any of the sub-cells. For this reason, it is desirable to provide a large number of cells (to increase voltage output) yet to provide that the current output of each cell is equal to the current output of each of the other cells.
- the general structure above provides that a larger number of Al x Ga 1-x As tandem sub-cells may be provided since the Al x Ga 1-x As layers are lattice matched independent of x, which determines the material's bandgap energy.
- the device also employs silicon (Si) as an active tandem sub-cell as well as a mechanical substrate and epitaxial substrate. Further, the device employs ultra thin Ge buffer layers that as used for lattice mismatch accommodation between Al x Ga 1-x As and Si, as well Ge and Si.
- the thin Ge buffer layers may be grown using ultra high vacuum chemical vapor deposition (UHV-CVD) growth followed by thermal cyclic annealing as disclosed in U.S. Pat. No.
- the Ge cell provides a bottom tandem cell for collecting photons that would otherwise be wasted.
- the epi-growth may be achieved, for example, via high-throughput chemical vapor deposition reactors capable of many-wafer-growth in a single batch, or hot wire chemical vapor deposition.
- the process of making the device 10 begins (step 200 ) by growing an ultra thin Ge buffer layer on both sides ( 20 and 22 ) of the Si cell 18 (step 202 ).
- the Ge cell 24 is then grown on the bottom side of the Si cell 18 (step 204 ), and the device then undergoes post-growth annealing (step 206 ).
- the Al y Ga 1-y As cell 14 is then grown on the Ge buffer layer 20 (step 208 ), followed again by post-growth annealing (step 210 ).
- the AlGaAs tunnel junction layer 16 is then grown on the Al y Ga 1-y As cell 14 (step 212 ), and the second Al x Ga 1-x As cell 12 is grown on the tunnel junction layer 16 .
- AlGaAs is a well studied lattice matched system to Ge for all compositions, allowing for a range of choices of the band gaps of the top two cells and thus current matching.
- the materials system proposed here includes the use of Si and Ge, which allows for the use of multiple SiGe layers on the backside of Si (as discussed below with reference to FIG. 5 ), allowing for up to an 8 layer, current-matched tandem cell to be made using this basic system.
- the Si lattice constant is smaller than that of the other materials considered here, such as AlGaAs and Ge.
- the Si plays the role of a solar cell as well as that of a mechanical and epitaxial substrate, so thick SiGe buffer growth technology is not necessary.
- the presence of a thick SiGe buffer layer between the AlGaAs and Si cells would absorb too many photons, robbing the bottom Si and Ge sub-cells of current and not allowing for efficient current matching.
- the Ge buffer growth technology mentioned above is desirable because it can produce a buffer layer thinner than approximately 60 nm. In any event, the effect of the buffer layers on photon absorption is not negligible.
- the thicker the Ge buffer the fewer photons will be transmitted to the lower-positioned Si and Ge layers.
- the Al content of the AlGaAs layers, and accordingly the bandgap energy must be made higher than the ideal calculated to reduce current generated in this layer as the Ge buffer thickness increases, to allow current matching with the lower Si and Ge cells which will lose some current due to the thicker Ge buffer.
- Tunneling junctions must be placed between the AlGaAs tandem cells as discussed above.
- the doping profile should be sharp, requiring low temperature growth.
- the development of dual hetero-structure AlGaAs tunnel junctions is provided by the use of low temperature Ge buffer layers and post-growth cyclical annealing to substantially reduce dislocation density below 10 7 cm ⁇ 2 in the Ge epilayers.
- a graph 40 of the total cumulative photocurrent available from absorption of all light in the solar spectrum in mA/cm 2 versus wavelength shows that if the thickness and bandgap energy of each cell is chosen appropriately, the current output of each cell may be equal to that of the other cells (e.g., 13 mA/cm 2 as shown).
- FIG. 3 a graph 40 of the total cumulative photocurrent available from absorption of all light in the solar spectrum in mA/cm 2 versus wavelength shows that if the thickness and bandgap energy of each cell is chosen appropriately, the current output of each cell may be equal to that of the other cells (e.g., 13 mA/cm 2 as shown).
- the Al x Ga 1-x As cell 12 provides a photovoltaic response to solar energy with wavelength shorter than about 600 nm
- the Al y Ga 1-y As cell 14 provides a photovoltaic response to solar energy in the wavelength range of about 600-800 nm
- the Si cell 18 provides a photovoltaic response to solar energy in the wavelength range of about 800-1100 nm
- the Ge cell 24 provides a photovoltaic response to solar energy in the wavelength range of about 1100-1600 nm.
- the post-growth annealing can alter the dopant profiles in the cells that are fabricated before it occurs.
- the most sensitive doping profile is at the AlGaAs tunnel junction between the AlGaAs/AlGaAs tandem sub-cells. Accordingly, in the multiple AlGaAs layer tandem cells described here, only the first AlGaAs layer that is deposited before the AlGaAs tunnel junction can be post-growth annealed. Since the first high-quality AlGaAs layer serves as a growth template for further AlGaAs layers, this does not represent a problem here.
- FIG. 4 shows an illustrative diagrammatic band energy diagram for the device 10 of FIG. 1 .
- the Al x Ga 1-x As cell 12 cell has a band structure as shown at 50
- the Al y Ga 1-y As cell 14 cell has a band structure as shown at 52
- the Si cell 18 cell has a band structure as shown at 58
- the Ge cell has a band structure as shown at 62 .
- the band structure of the coupling layers is also shown in FIG. 4
- the band structure of the AlGaAs tunnel junction layer 16 is shown at 52
- the band structure of the Ge buffer layers 20 and 22 is are shown at 56 and 60 respectively.
- ultra thin Ge buffers of high enough quality must be grown to allow for the growth of high quality Ge and AlGaAs cells thereon. It is important that the Ge buffer be as thin as possible, and preferably that it be thinner than 50 nm. A 60 nm Ge buffer layer has proven to be sufficient to produce high quality thick Ge-on-Si films.
- a photovoltaic device 100 in accordance with another embodiment of the invention is shown in FIG. 5 .
- the device 100 includes a Si cell 102 with two ultra thin Ge buffer layers ( 104 and 106 ) on either side of the Si cell 102 .
- Onto the first Ge buffer layer 104 is grown a plurality of AlGaAs cells separated by AlGaAs tunnel junction layers.
- an Al z Ga 1-z As cell 108 is shown grown on the Ge buffer layer 104 , followed by an AlGaAs tunnel junction layer 110 , followed by an Al y Ga 1-z As cell 112 .
- the process of growing AlGaAs layers and AlGaAs tunnel junction layers continues with increasing Al contents in the AlGaAs cell layers, until the final AlGaAs tunnel junction layer 114 and the final top Al x Ga 1-x As cell 116 is grown.
- a SiGe cell 118 is shown grown on the Ge buffer layer 106 , followed by a SiGe tunnel junction layer 120 , followed by a Si v Ge 1-v cell 122 .
- the process of growing SiGe layers and SiGe tunnel junction layers continues with increasing Ge contents in the SiGe cell layers, until the final SiGe tunnel junction layer 124 and Si w Ge 1-w cell 126 is grown. Note that this final composition may include a pure Ge layer.
- Conductors 130 and 132 are applied to the top and bottom of the device for providing power output at terminals 134 and 136 .
- tandem cells in accordance with various embodiments may provide a variety of combinations of the above materials, including the following.
- a tandem cell may include (from top to bottom), an AlGaAs cell, a Ge buffer layer, a Si cell, another Ge buffer layer, and a Ge cell.
- Another tandem cell may include two or three AlGaAs cells separated by an AlGaAs tunnel junction layer followed by a Ge buffer layer, a Si cell, another Ge buffer layer, and a SiGe cell where the Si content may be zero.
- Another tandem cell may include four or five AlGaAs cells separated by AlGaAs tunnel junction layers, followed by a Ge buffer layer, a Si cell, another Ge buffer layer, and one, two or three SiGe cells, wherein the Si content of the bottom layer may be zero.
- Another tandem cell may include an AlGaAs cell followed by a Ge buffer layer, and a Si cell.
- Another tandem cell may include two, three or four AlGaAs cells separate by tunnel junction layers followed by a Ge buffer layer, and a Si cell.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Photovoltaic Devices (AREA)
Abstract
Description
- The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/497,167 filed Aug. 22, 2003.
- The invention relates to the field of solar cells, and in particular to tandem solar cells.
- Photovoltaic cells, commonly known as solar cells, are devices that convert light energy into electric energy. Solar cells provide a number of distinct advantages when compared to conventional energy sources. For example, solar cells produce electricity without any harmful emissions and do not rely on finite fossil fuel supplies. Furthermore, solar cells create electric power without any active supply of fuel and thus can serve as sources of electric power in remote terrestrial locations as well as in space.
- Currently, the most widely deployed solar cell devices consist of a single solar cell made of silicon (Si). These Si solar cells have been perfected to a level that they have very nearly reached their theoretical efficiency limit of ˜26% in conversion of solar energy to electricity. Silicon solar cells produce electricity more cost-effectively than any other type of solar cell. Even so, however, the current cheapest Si solar cells prices of ˜$3/peak watt of electric power generation still result in electricity prices of 25-40 cents/kWh, at least 5 times the current electricity price from conventional energy sources such as coal and natural gas. Thus, the quest to develop new solar cell devices with higher efficiency and lower cost than that achieved with single silicon solar cells continues in industry and academia with great interest.
- One of the most promising technologies for realizing solar cells with higher efficiency and lower cost relative to silicon solar cells is that of tandem solar cells. For example, U.S. Pat. Nos. 6,340,788 and 5,009,719 as well as U.S. Published Patent Applications Nos. 2004/0079408 and 2002/0179142 disclose tandem solar cells. In a tandem solar cell, multiple solar cells consisting of different materials are stacked upon each other. In order for electricity to be produced from light, a solar cell must be able to perform two primary functions: 1) it must be able to absorb the incident sunlight to produce free electronic carriers and 2) it must be able to collect these carriers to produce electric power. The ability of a solar cell to absorb sunlight is determined by an intrinsic materials property called the bandgap energy. A material with a given bandgap energy has the ability to absorb sunlight of energy equal to or greater than its bandgap. Most of sunlight energy falls in the energy range from 0.50 eV-4.13 eV and the solar spectrum peaks at approximately 2.5 eV. As a note, the wavelength, λ, and energy, E, of light can be interconverted using λ(μm)=1.239/E(eV). Accordingly, light energies and bandgap energies can be converted to light wavelengths and bandgap wavelengths. The only difference in this case is that a material having a given bandgap wavelength can only absorb light wavelengths smaller than its bandgap wavelength. A further important consideration in tandem solar cells is that a solar cell consisting of a material with a given bandgap energy converts light energy most efficiently in a narrow range of energies just above its bandgap energy.
- According to all these considerations, in order to absorb sunlight as efficiently as possible a tandem solar cell must consist of a stack of multiple photovoltaic cells consisting of a highest bandgap material on the side upon which light is incident, with many successive layers beneath it having progressively lower bandgaps. Such a structure results in two advantages: 1) a larger portion of the sunlight spectrum is absorbed and 2) more of the sunlight absorbed is absorbed at energies close to the bandgap energies of the cells of which the tandem cell consists, resulting in higher efficiencies within each individual cell, and thus higher efficiency for the tandem cell.
- An additional key consideration in the design of tandem solar cells is that the net tandem solar cell device current is dictated by the lowest current present in any of the Individual sub-cells within the tandem solar cell. Accordingly, current-matching between all sub-cells is ideal and puts a further constraint on the bandgaps that the materials of the sub-cells must have in order for a tandem cell to exhibit high efficiency. Effectively, the materials must be selected to apportion the absorption and collection of free charge carriers from sunlight evenly, which requires the sub-cells to have very specific sets of bandgap energy values for optimum efficiency. The maximum efficiency of a current-matched tandem solar cell generally increases with the number of sub-cells, and accordingly a larger number of current-matched sub-cells is preferable to a smaller number with regard to maximizing tandem solar cell device efficiency.
- As mentioned previously, however, solar cells must not only absorb sunlight, but also must collect the light-generated free electronic carriers that are generated, in order to produce electric power. In order for a solar cell to efficiently collect these carriers, the solar cell materials must be of as high crystalline perfection as possible. Traditionally, in order to easily grow high crystalline quality solar cell materials on top of one another, as required in a tandem solar cell, all the different solar cell materials within one tandem cell have had to have identical crystalline structures with the same lattice constant in order for high-quality tandem cells with high efficiency to be produced. Materials systems with this property are called lattice-matched. When a material is grown upon another material with a different crystalline structure or lattice constant, crystalline defects such as misfit and threading dislocations that degrade the crystalline structure and free electronic carrier collection are formed in the grown material. Accordingly, lattice-mismatched materials systems typically have low solar cell efficiency performance. The highest efficiency tandem solar cells fabricated to date, demonstrating efficiencies of ˜30%, consist of lattice-matched GaInP2/GaAs/Ge structures based upon expensive Ge substrate materials technology. Accordingly, these tandem cells have prohibitive costs for typical solar cell application and will not exceed the cost performance of single silicon solar cells.
- A solution to the current solar cell cost problem would be to merge the high-efficiency of tandem solar cells with the low-cost of silicon substrate-based solar cells. An ideal embodiment would include a high-efficiency tandem solar cell consisting of as many current-matched, high crystalline quality sub-cells as possible integrated onto an inexpensive silicon substrate which is used as a growth substrate and an active tandem cell sub-cell. A critical problem, however, is that there exist no common materials that are lattice-matched to silicon that can provide the bandgap values required for the necessary absorption over the whole solar spectrum, along with tandem cell sub-cell current matching. Accordingly, attempts to date to make tandem solar cells on silicon substrates have resulted in high threading dislocation density (˜109 dislocation/cm2) and poor crystalline quality; and thus accordingly have poor solar energy conversion efficiency.
- Attempts to date have focused on two distinct strategies: 1) growth of lattice mismatched layers directly on Si with or without low quality, thick buffers and 2) graded, buffer technologies in order to alleviate the lattice-mismatch problem and grow pseudo-lattice matched layers on Si. The former method has been attempted and has resulted in low quality (˜109 dislocations/cm2), low efficiency cells. The latter method has involved growing relatively high quality (˜106 dislocations/cm2) GaInP2/GaAs/Ge three sub-cell tandem solar cells on silicon substrates using thick (˜10 μm) layers of SiGe, grading from pure Si at the silicon substrate, through a number of layers of SiGe of increasing Ge concentration up to pure Ge, and by then growing GaAs and GaInP2 lattice-matched to the Ge layer. This method however, has the disadvantage that due to the thick SiGe buffer, it is not possible to integrate the buffer or any layers beneath it into the active tandem cell structure.
- There remains a need, therefore, for solar cells that are economical to produce and provide more efficient conversion of light into electrical energy.
- A system is disclosed for providing electrical power responsive to solar energy. In accordance with an embodiment, the system includes a Si cell, an AlGaAs cell, and a Ge cell. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range. The Ge cell is coupled to a second side of the Si cell, and the Ge cell provides electrical power responsive to solar energy within a third frequency range.
- In accordance with another embodiment, the system includes a Si cell, a first AlGaAs cell, a second AlGaAs cell, and a Ge cell. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The first AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range. The second AlGaAs cell is coupled to the first AlGaAs cell, and is for providing electrical power responsive to solar energy within a third frequency range. The Ge cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to solar energy within a fourth frequency range.
- In accordance with another embodiment the system includes a Si cell, an AlGaAs cell and a Ge buffer layer. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range. The Ge buffer layer is less than about 60 nm in thickness and is positioned between the Si cell and the AlGaAs cell.
- In accordance with yet another embodiment, the system includes a Si cell, first and second AlGaAs cells and a first SiGe cell. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The first AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to a solar energy within a second frequency range. The second AlGaAs cell is coupled to the first AlGaAs cell, and is for providing electrical power responsive to a solar energy within a third frequency range. The first SiGe cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to a solar energy within a fourth frequency range.
- The following detailed description may be further understood with reference to the accompanying drawings in which:
-
FIG. 1 shows an illustrative diagrammatic side view of a photovoltaic device in accordance with an embodiment of the invention; -
FIG. 2 shows an illustrative diagrammatic flowchart of a method of forming the device shown inFIG. 1 ; -
FIG. 3 shows an illustrative graphical view of total collected photocurrent under the AM1.5 solar spectrum versus wavelength for a device as shown inFIG. 1 ; -
FIG. 4 shows an illustrative diagrammatic view of an energy diagram for a device as shown inFIG. 1 ; and -
FIG. 5 shows an illustrative diagrammatic side view of a photovoltaic device in accordance with another embodiment of the invention. - The drawings are shown for illustrative purposes only and are not to scale.
- Applicants have discovered that tandem cell structures based upon silicon substrates may be formed in accordance with various embodiments of the invention. The materials Ge, AlAs, GaAs, AlxGa1-xAs (consisting of all compositions intermediate between AlAs (2.67 eV(direct)) and GaAs (1.42 eV)), and GaInP2 are all lattice-matched and offer a wide variety of bandgap values. For example, a four sub-cell tandem cell based upon Ge on the backside and two AlGaAs top cells of different compositions on the front-side may be optimized if a material having a bandgap of ˜1.0 eV is placed between the Ge and the AlGaAs layers. Fortuitously, silicon's bandgap of 1.12 eV is very well suited for this layer. Furthermore, the use of a high-quality ultra-thin Ge growth buffer on each side of a silicon wafer allows for the high-quality growth of both Ge and all compositions of AlGaAs on Si. The added fact that such a thin Ge buffer is sufficient for high-quality Ge and AlGaAs growth on Si greatly minimizes the parasitic absorption that inevitably occurs in low bandgap growth buffers and makes this cell structure highly promising for a highly-efficient, low-cost tandem solar cell technology.
- Such high quality germanium layers may be grown directly on silicon by use of an ultra high vacuum chemical vapor deposition (UHV-CVD) low temperature germanium buffer layer deposition followed by thermal cyclic annealing. The formation of such high quality germanium layers with low threading dislocation densities of ˜107 cm−2 using germanium buffer layers of ˜50 nm have been demonstrated in U.S. Pat. No. 6,625,110. An object of this invention is to provide high-efficiency tandem solar cells on low-cost silicon substrates. This is achieved, in part, through the use of ultra-thin high-quality Ge growth buffer layers grown by ultra high vacuum chemical vapor deposition.
- A system is disclosed for providing electrical power responsive to solar energy within a wide range of energies. In accordance with an embodiment, the system includes a Si substrate-based cell, a grown AlGaAs cell, and a grown Ge cell. The grown AlGaAs cell is coupled to a first side of the Si cell, the side upon which light is incident, and is for providing electrical power responsive to high energy solar energy. The Si substrate-based cell is for providing electrical power responsive to solar energy at intermediate energies. The grown Ge cell is coupled to a second side of the Si cell, and the Ge cell provides electrical power responsive to solar energy at low energies. The exact composition of the AlGaAs sub-cell material is of such a composition as to provide current matching with the Si and Ge sub-cells and is dependent upon the exact thickness of each sub-cell.
- In accordance with another embodiment, the system includes a Si cell, a first AlyGa1-yAs cell, a second AlxGa1-xAs cell, and a Ge cell. The bandgap of the second AlxGa1-xAs cell is larger than that of the first AlyGa1-yAs cell in this embodiment, requiring that 1>x>y>0. The first AlyGa1-yAs cell is coupled to a first side of the Si cell, the side upon which light is made incident. The second AlxGa1-yAs cell is coupled on the side of the first AlyGa1-yAs opposite the Si substrate. The Ge cell is coupled to the second side of the Si substrate-based cell. The second AlxGa1-xAs cell is for providing electric power responsive to solar energy of high energy. The first AlyGa1-yAs cell is for providing electric power responsive to solar energy of slightly lower energy. The Si substrate-based cell is for providing electric power responsive to solar energy of even lower energy. The Ge cell is for providing electric power responsive to solar energy of the lowest energy.
- In accordance with another embodiment the system includes a Si cell, an AlGaAs cell and a Ge buffer layer. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The AlGaAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range. The Ge buffer layer is less than about 60 nm in thickness and is positioned between the Si cell and the AlGaAs cell.
- In accordance with yet another embodiment, the system includes a Si cell, first and second AlGaAs cells and a first SiGe cell. The Si cell is for providing electrical power responsive to solar energy within a first frequency range. The first AlyGa1-yAs cell is coupled to a first side of the Si cell, and is for providing electrical power responsive to solar energy within a second frequency range. The second AlxGa1-xAs cell is coupled to the first AlyGa1-yAs cell, and is for providing electrical power responsive to solar energy within a third frequency range. The first SiGe cell is coupled to a second side of the Si cell, and is for providing electrical power responsive to solar energy within a fourth frequency range. In further embodiments, a high bandgap AlGaAs layer may be provided on the top surface of the device for surface passivation to make the surface electrically inactive.
- As shown in
FIG. 1 , aphotovoltaic device 10 in accordance with an embodiment of the invention includes afirst cell 12 formed of AlxGa1-xAs, and asecond cell 14 formed of AlyGa1-yAs that are coupled to one another via anAlGaAs tunnel junction 16. Thedevice 10 also includes aSi cell 18 that is coupled to the AlyGa1-yAscell 14 via an ultra thinGe buffer layer 20. Another ultra thinGe buffer layer 22 is formed on the backside of theSi cell 18, and aGe cell 24 is formed on theGe buffer layer 22.Electrical conductors device 10 for connecting topower output terminals - The
cells - The general structure above provides that a larger number of AlxGa1-xAs tandem sub-cells may be provided since the AlxGa1-xAs layers are lattice matched independent of x, which determines the material's bandgap energy. The device also employs silicon (Si) as an active tandem sub-cell as well as a mechanical substrate and epitaxial substrate. Further, the device employs ultra thin Ge buffer layers that as used for lattice mismatch accommodation between AlxGa1-xAs and Si, as well Ge and Si. The thin Ge buffer layers may be grown using ultra high vacuum chemical vapor deposition (UHV-CVD) growth followed by thermal cyclic annealing as disclosed in U.S. Pat. No. 6,635,110, the disclosure of which is hereby incorporated by reference. The Ge cell provides a bottom tandem cell for collecting photons that would otherwise be wasted. The epi-growth may be achieved, for example, via high-throughput chemical vapor deposition reactors capable of many-wafer-growth in a single batch, or hot wire chemical vapor deposition.
- Analytical results have demonstrated that efficiency of the tandem device with four AlGaAs cells, a Si substrate cell, and a Ge backside sub-cell could be as high as 47% under one sun, and as high as 52.5% using a concentrator (e.g., 100 suns). The efficiencies should also increase with a tandem device having up to five AlGaAs cells. At this number of cells, the fixed bandgap energy difference between GaAs and Si does not allow for current matching with added AlGaAs cells. These high efficiencies are achieved, in part, due to the use of Ge buffer layers for lattice-matching between the AlGaAs and Si cells, and between the Ge and Si cells, as well as due to the AlGaAs growth on the Ge buffer and the use of the tunnel junctions between the AlGaAs cells.
- As shown in
FIG. 2 , the process of making thedevice 10 begins (step 200) by growing an ultra thin Ge buffer layer on both sides (20 and 22) of the Si cell 18 (step 202). TheGe cell 24 is then grown on the bottom side of the Si cell 18 (step 204), and the device then undergoes post-growth annealing (step 206). The AlyGa1-yAscell 14 is then grown on the Ge buffer layer 20 (step 208), followed again by post-growth annealing (step 210). The AlGaAstunnel junction layer 16 is then grown on the AlyGa1-yAs cell 14 (step 212), and the second AlxGa1-xAscell 12 is grown on thetunnel junction layer 16. - AlGaAs is a well studied lattice matched system to Ge for all compositions, allowing for a range of choices of the band gaps of the top two cells and thus current matching. The (AlGaAs)m/(Ge)/Si/(Ge)/Ge tandem cell structure proposed herein with m=1-5 provides absorption of light of wavelength shorter than the Ge direct band gap (−1600 nm) in the spectrum AM 1.5 G. This enhances the efficiency to higher than 50% with m=4 and further for m=5. This performance corresponds to collection of more than 75% photons in the AM 1.5 G spectrum below 4000 nm. This seamless increase of m is an advantage of using the AlGaAs system. Furthermore, the materials system proposed here includes the use of Si and Ge, which allows for the use of multiple SiGe layers on the backside of Si (as discussed below with reference to
FIG. 5 ), allowing for up to an 8 layer, current-matched tandem cell to be made using this basic system. - The Si lattice constant is smaller than that of the other materials considered here, such as AlGaAs and Ge. As mentioned above, the Si plays the role of a solar cell as well as that of a mechanical and epitaxial substrate, so thick SiGe buffer growth technology is not necessary. The presence of a thick SiGe buffer layer between the AlGaAs and Si cells would absorb too many photons, robbing the bottom Si and Ge sub-cells of current and not allowing for efficient current matching. The Ge buffer growth technology mentioned above is desirable because it can produce a buffer layer thinner than approximately 60 nm. In any event, the effect of the buffer layers on photon absorption is not negligible. In general, the thicker the Ge buffer, the fewer photons will be transmitted to the lower-positioned Si and Ge layers. For thicker Ge buffers, the Al content of the AlGaAs layers, and accordingly the bandgap energy, must be made higher than the ideal calculated to reduce current generated in this layer as the Ge buffer thickness increases, to allow current matching with the lower Si and Ge cells which will lose some current due to the thicker Ge buffer. This is a built-in aspect of this invention that requires it to entail a range of layer thicknesses and AlxGa1-xAs compositions within its definition.
- Tunneling junctions must be placed between the AlGaAs tandem cells as discussed above. The doping profile should be sharp, requiring low temperature growth. The development of dual hetero-structure AlGaAs tunnel junctions is provided by the use of low temperature Ge buffer layers and post-growth cyclical annealing to substantially reduce dislocation density below 107 cm−2 in the Ge epilayers.
- As shown in
FIG. 3 , agraph 40 of the total cumulative photocurrent available from absorption of all light in the solar spectrum in mA/cm2 versus wavelength shows that if the thickness and bandgap energy of each cell is chosen appropriately, the current output of each cell may be equal to that of the other cells (e.g., 13 mA/cm2 as shown).FIG. 3 shows that the AlxGa1-xAscell 12 provides a photovoltaic response to solar energy with wavelength shorter than about 600 nm, the AlyGa1-yAscell 14 provides a photovoltaic response to solar energy in the wavelength range of about 600-800 nm, theSi cell 18 provides a photovoltaic response to solar energy in the wavelength range of about 800-1100 nm, and theGe cell 24 provides a photovoltaic response to solar energy in the wavelength range of about 1100-1600 nm. - The post-growth annealing can alter the dopant profiles in the cells that are fabricated before it occurs. The most sensitive doping profile is at the AlGaAs tunnel junction between the AlGaAs/AlGaAs tandem sub-cells. Accordingly, in the multiple AlGaAs layer tandem cells described here, only the first AlGaAs layer that is deposited before the AlGaAs tunnel junction can be post-growth annealed. Since the first high-quality AlGaAs layer serves as a growth template for further AlGaAs layers, this does not represent a problem here.
-
FIG. 4 shows an illustrative diagrammatic band energy diagram for thedevice 10 ofFIG. 1 . The AlxGa1-xAscell 12 cell has a band structure as shown at 50, the AlyGa1-yAscell 14 cell has a band structure as shown at 52, theSi cell 18 cell has a band structure as shown at 58, and the Ge cell has a band structure as shown at 62. The band structure of the coupling layers is also shown inFIG. 4 , and the band structure of the AlGaAstunnel junction layer 16 is shown at 52, while the band structure of the Ge buffer layers 20 and 22 is are shown at 56 and 60 respectively. - It is desirable to grow low dislocation density Ge and AlGaAs on ultra thin Ge buffers for certain embodiments of the invention. Also, ultra thin Ge buffers of high enough quality must be grown to allow for the growth of high quality Ge and AlGaAs cells thereon. It is important that the Ge buffer be as thin as possible, and preferably that it be thinner than 50 nm. A 60 nm Ge buffer layer has proven to be sufficient to produce high quality thick Ge-on-Si films.
- A
photovoltaic device 100 in accordance with another embodiment of the invention is shown inFIG. 5 . Thedevice 100 includes aSi cell 102 with two ultra thin Ge buffer layers (104 and 106) on either side of theSi cell 102. Onto the firstGe buffer layer 104 is grown a plurality of AlGaAs cells separated by AlGaAs tunnel junction layers. In particular, an AlzGa1-zAscell 108 is shown grown on theGe buffer layer 104, followed by an AlGaAstunnel junction layer 110, followed by an AlyGa1-zAscell 112. The process of growing AlGaAs layers and AlGaAs tunnel junction layers continues with increasing Al contents in the AlGaAs cell layers, until the final AlGaAstunnel junction layer 114 and the final top AlxGa1-xAs cell 116 is grown. - Similarly, onto the second
Ge buffer layer 106 is grown a plurality of SiGe cells separated by SiGe tunnel junction layers. In particular, a SiuGe1-u cell 118 is shown grown on theGe buffer layer 106, followed by a SiGetunnel junction layer 120, followed by a SivGe1-v cell 122. The process of growing SiGe layers and SiGe tunnel junction layers continues with increasing Ge contents in the SiGe cell layers, until the final SiGetunnel junction layer 124 and SiwGe1-w cell 126 is grown. Note that this final composition may include a pure Ge layer.Conductors 130 and 132 are applied to the top and bottom of the device for providing power output atterminals - Examples of tandem cells in accordance with various embodiments may provide a variety of combinations of the above materials, including the following. A tandem cell may include (from top to bottom), an AlGaAs cell, a Ge buffer layer, a Si cell, another Ge buffer layer, and a Ge cell. Another tandem cell may include two or three AlGaAs cells separated by an AlGaAs tunnel junction layer followed by a Ge buffer layer, a Si cell, another Ge buffer layer, and a SiGe cell where the Si content may be zero. Another tandem cell may include four or five AlGaAs cells separated by AlGaAs tunnel junction layers, followed by a Ge buffer layer, a Si cell, another Ge buffer layer, and one, two or three SiGe cells, wherein the Si content of the bottom layer may be zero. Another tandem cell may include an AlGaAs cell followed by a Ge buffer layer, and a Si cell. Another tandem cell may include two, three or four AlGaAs cells separate by tunnel junction layers followed by a Ge buffer layer, and a Si cell.
- Those skilled in the art will appreciate that numerous modifications and variations may be made to the above disclosed embodiments without departing from the spirit and scope of the invention.
Claims (30)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/922,420 US20050081910A1 (en) | 2003-08-22 | 2004-08-20 | High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US49716703P | 2003-08-22 | 2003-08-22 | |
US10/922,420 US20050081910A1 (en) | 2003-08-22 | 2004-08-20 | High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050081910A1 true US20050081910A1 (en) | 2005-04-21 |
Family
ID=34216087
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/922,420 Abandoned US20050081910A1 (en) | 2003-08-22 | 2004-08-20 | High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers |
Country Status (2)
Country | Link |
---|---|
US (1) | US20050081910A1 (en) |
WO (1) | WO2005020334A2 (en) |
Cited By (36)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040267373A1 (en) * | 2003-06-25 | 2004-12-30 | Dwyer Kimberly Ann | Assembly tool for modular implants and associated method |
US20050033444A1 (en) * | 2003-06-25 | 2005-02-10 | Jones Michael C. | Assembly tool for modular implants and associated method |
US20090250096A1 (en) * | 2008-04-07 | 2009-10-08 | Eric Ting-Shan Pan | Solar-To-Electricity Conversion Sub-Module |
US20100218807A1 (en) * | 2009-02-27 | 2010-09-02 | Skywatch Energy, Inc. | 1-dimensional concentrated photovoltaic systems |
US20100319684A1 (en) * | 2009-05-26 | 2010-12-23 | Cogenra Solar, Inc. | Concentrating Solar Photovoltaic-Thermal System |
US20110017267A1 (en) * | 2009-11-19 | 2011-01-27 | Joseph Isaac Lichy | Receiver for concentrating photovoltaic-thermal system |
US20110232733A1 (en) * | 2010-03-29 | 2011-09-29 | Astrium Gmbh | Multi-Junction Solar Cell For Space Applications |
US20130056053A1 (en) * | 2011-09-02 | 2013-03-07 | Amberwave Inc. | Solar cell |
WO2013106000A1 (en) * | 2011-02-16 | 2013-07-18 | Caelux Corporation | Wire array solar cells employing multiple junctions |
US8518050B2 (en) | 2007-10-31 | 2013-08-27 | DePuy Synthes Products, LLC | Modular taper assembly device |
US8669462B2 (en) | 2010-05-24 | 2014-03-11 | Cogenra Solar, Inc. | Concentrating solar energy collector |
US20140076388A1 (en) * | 2012-09-14 | 2014-03-20 | The Boeing Company | GROUP-IV SOLAR CELL STRUCTURE USING GROUP-IV or III-V HETEROSTRUCTURES |
US8686279B2 (en) | 2010-05-17 | 2014-04-01 | Cogenra Solar, Inc. | Concentrating solar energy collector |
US8852994B2 (en) | 2010-05-24 | 2014-10-07 | Masimo Semiconductor, Inc. | Method of fabricating bifacial tandem solar cells |
US8998919B2 (en) | 2003-06-25 | 2015-04-07 | DePuy Synthes Products, LLC | Assembly tool for modular implants, kit and associated method |
US20150144192A1 (en) * | 2007-08-17 | 2015-05-28 | Basf Se | Solar cell structure |
US9095452B2 (en) | 2010-09-01 | 2015-08-04 | DePuy Synthes Products, Inc. | Disassembly tool |
US9101495B2 (en) | 2010-06-15 | 2015-08-11 | DePuy Synthes Products, Inc. | Spiral assembly tool |
US9270225B2 (en) | 2013-01-14 | 2016-02-23 | Sunpower Corporation | Concentrating solar energy collector |
US9353973B2 (en) | 2010-05-05 | 2016-05-31 | Sunpower Corporation | Concentrating photovoltaic-thermal solar energy collector |
US9504578B2 (en) | 2011-04-06 | 2016-11-29 | Depuy Synthes Products, Inc | Revision hip prosthesis having an implantable distal stem component |
US9530921B2 (en) | 2014-10-02 | 2016-12-27 | International Business Machines Corporation | Multi-junction solar cell |
US9717545B2 (en) | 2007-10-30 | 2017-08-01 | DePuy Synthes Products, Inc. | Taper disengagement tool |
CN107195712A (en) * | 2017-06-12 | 2017-09-22 | 广东爱康太阳能科技有限公司 | A kind of silicon class binode lamination solar cell |
US20180254357A1 (en) * | 2017-03-03 | 2018-09-06 | Solaero Technologies Corp. | Distributed bragg reflector structures in multijunction solar cells |
US10896990B2 (en) | 2012-09-14 | 2021-01-19 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US10903383B2 (en) | 2012-09-14 | 2021-01-26 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
CN113206164A (en) * | 2021-04-26 | 2021-08-03 | 宜兴市昱元能源装备技术开发有限公司 | Cast tandem multi-junction photovoltaic cell |
US11133429B2 (en) | 2012-09-14 | 2021-09-28 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US20220020890A1 (en) * | 2019-06-03 | 2022-01-20 | Suzhou Institute Of Nano-Tech And Nano-Bionics (Sinano), Chinese Academy Of Sciences | Multi-junction laminated laser photovoltaic cell |
US11245046B2 (en) * | 2017-04-17 | 2022-02-08 | Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences | Multi-junction tandem laser photovoltaic cell and manufacturing method thereof |
US11282979B2 (en) * | 2017-03-03 | 2022-03-22 | Solaero Technologies Corp. | Distributed bragg reflector structures in multijunction solar cells |
US11495705B2 (en) | 2012-09-14 | 2022-11-08 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US11595000B2 (en) | 2012-11-08 | 2023-02-28 | Maxeon Solar Pte. Ltd. | High efficiency configuration for solar cell string |
US11646388B2 (en) | 2012-09-14 | 2023-05-09 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US12107182B2 (en) | 2020-10-19 | 2024-10-01 | The Boeing Company | Group-IV solar cell structure using group-IV heterostructures |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110254052A1 (en) * | 2008-10-15 | 2011-10-20 | Arizona Board of Regents, a body corporate acting for and on behalf of Arizona State University | Hybrid Group IV/III-V Semiconductor Structures |
CN103311354B (en) * | 2013-05-30 | 2017-01-25 | 中国科学院苏州纳米技术与纳米仿生研究所 | Si substrate three-junction cascade solar cell and fabrication method thereof |
Citations (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3836399A (en) * | 1970-02-16 | 1974-09-17 | Texas Instruments Inc | PHOTOVOLTAIC DIODE WITH FIRST IMPURITY OF Cu AND SECOND OF Cd, Zn, OR Hg |
US4155371A (en) * | 1978-09-25 | 1979-05-22 | Atlantic Richfield Company | Luminescent solar collector |
US4370510A (en) * | 1980-09-26 | 1983-01-25 | California Institute Of Technology | Gallium arsenide single crystal solar cell structure and method of making |
US4547622A (en) * | 1984-04-27 | 1985-10-15 | Massachusetts Institute Of Technology | Solar cells and photodetectors |
US4551394A (en) * | 1984-11-26 | 1985-11-05 | Honeywell Inc. | Integrated three-dimensional localized epitaxial growth of Si with localized overgrowth of GaAs |
US4579609A (en) * | 1984-06-08 | 1986-04-01 | Massachusetts Institute Of Technology | Growth of epitaxial films by chemical vapor deposition utilizing a surface cleaning step immediately before deposition |
US4632712A (en) * | 1983-09-12 | 1986-12-30 | Massachusetts Institute Of Technology | Reducing dislocations in semiconductors utilizing repeated thermal cycling during multistage epitaxial growth |
US5009719A (en) * | 1989-02-17 | 1991-04-23 | Mitsubishi Denki Kabushiki Kaisha | Tandem solar cell |
US5403405A (en) * | 1992-06-30 | 1995-04-04 | Jx Crystals, Inc. | Spectral control for thermophotovoltaic generators |
US5437734A (en) * | 1993-02-08 | 1995-08-01 | Sony Corporation | Solar cell |
US5633527A (en) * | 1995-02-06 | 1997-05-27 | Sandia Corporation | Unitary lens semiconductor device |
US5913986A (en) * | 1996-09-19 | 1999-06-22 | Canon Kabushiki Kaisha | Photovoltaic element having a specific doped layer |
US6340788B1 (en) * | 1999-12-02 | 2002-01-22 | Hughes Electronics Corporation | Multijunction photovoltaic cells and panels using a silicon or silicon-germanium active substrate cell for space and terrestrial applications |
US20020178142A1 (en) * | 2001-03-26 | 2002-11-28 | Fujitsu Limited | Link tree forming apparatus, link tree forming method, and link tree forming program |
US20020190269A1 (en) * | 2001-04-17 | 2002-12-19 | Atwater Harry A. | Method of using a germanium layer transfer to Si for photovoltaic applications and heterostructure made thereby |
US6635110B1 (en) * | 1999-06-25 | 2003-10-21 | Massachusetts Institute Of Technology | Cyclic thermal anneal for dislocation reduction |
US20030216043A1 (en) * | 2002-02-28 | 2003-11-20 | Giovanni Flamand | Method for producing a device having a semiconductor layer on a lattice mismatched substrate |
US6713326B2 (en) * | 2000-08-16 | 2004-03-30 | Masachusetts Institute Of Technology | Process for producing semiconductor article using graded epitaxial growth |
US20040079408A1 (en) * | 2002-10-23 | 2004-04-29 | The Boeing Company | Isoelectronic surfactant suppression of threading dislocations in metamorphic epitaxial layers |
US20040112424A1 (en) * | 2002-10-03 | 2004-06-17 | Daido Steel Co., Ltd. | Solar cell assembly, and photovoltaic solar electric generator of concentrator type |
US20040154654A1 (en) * | 2001-05-16 | 2004-08-12 | Mortenson Mark G. | High efficiency solar cells |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2002303658A1 (en) * | 2001-05-08 | 2002-11-18 | Kimerling, Lionel, C. | Silicon solar cell with germanium backside solar cell |
-
2004
- 2004-08-20 WO PCT/US2004/027204 patent/WO2005020334A2/en active Application Filing
- 2004-08-20 US US10/922,420 patent/US20050081910A1/en not_active Abandoned
Patent Citations (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3836399A (en) * | 1970-02-16 | 1974-09-17 | Texas Instruments Inc | PHOTOVOLTAIC DIODE WITH FIRST IMPURITY OF Cu AND SECOND OF Cd, Zn, OR Hg |
US4155371A (en) * | 1978-09-25 | 1979-05-22 | Atlantic Richfield Company | Luminescent solar collector |
US4370510A (en) * | 1980-09-26 | 1983-01-25 | California Institute Of Technology | Gallium arsenide single crystal solar cell structure and method of making |
US4632712A (en) * | 1983-09-12 | 1986-12-30 | Massachusetts Institute Of Technology | Reducing dislocations in semiconductors utilizing repeated thermal cycling during multistage epitaxial growth |
US4547622A (en) * | 1984-04-27 | 1985-10-15 | Massachusetts Institute Of Technology | Solar cells and photodetectors |
US4579609A (en) * | 1984-06-08 | 1986-04-01 | Massachusetts Institute Of Technology | Growth of epitaxial films by chemical vapor deposition utilizing a surface cleaning step immediately before deposition |
US4551394A (en) * | 1984-11-26 | 1985-11-05 | Honeywell Inc. | Integrated three-dimensional localized epitaxial growth of Si with localized overgrowth of GaAs |
US5009719A (en) * | 1989-02-17 | 1991-04-23 | Mitsubishi Denki Kabushiki Kaisha | Tandem solar cell |
US5403405A (en) * | 1992-06-30 | 1995-04-04 | Jx Crystals, Inc. | Spectral control for thermophotovoltaic generators |
US5437734A (en) * | 1993-02-08 | 1995-08-01 | Sony Corporation | Solar cell |
US5633527A (en) * | 1995-02-06 | 1997-05-27 | Sandia Corporation | Unitary lens semiconductor device |
US5913986A (en) * | 1996-09-19 | 1999-06-22 | Canon Kabushiki Kaisha | Photovoltaic element having a specific doped layer |
US6635110B1 (en) * | 1999-06-25 | 2003-10-21 | Massachusetts Institute Of Technology | Cyclic thermal anneal for dislocation reduction |
US6340788B1 (en) * | 1999-12-02 | 2002-01-22 | Hughes Electronics Corporation | Multijunction photovoltaic cells and panels using a silicon or silicon-germanium active substrate cell for space and terrestrial applications |
US6713326B2 (en) * | 2000-08-16 | 2004-03-30 | Masachusetts Institute Of Technology | Process for producing semiconductor article using graded epitaxial growth |
US20020178142A1 (en) * | 2001-03-26 | 2002-11-28 | Fujitsu Limited | Link tree forming apparatus, link tree forming method, and link tree forming program |
US20020190269A1 (en) * | 2001-04-17 | 2002-12-19 | Atwater Harry A. | Method of using a germanium layer transfer to Si for photovoltaic applications and heterostructure made thereby |
US20040154654A1 (en) * | 2001-05-16 | 2004-08-12 | Mortenson Mark G. | High efficiency solar cells |
US20030216043A1 (en) * | 2002-02-28 | 2003-11-20 | Giovanni Flamand | Method for producing a device having a semiconductor layer on a lattice mismatched substrate |
US20040112424A1 (en) * | 2002-10-03 | 2004-06-17 | Daido Steel Co., Ltd. | Solar cell assembly, and photovoltaic solar electric generator of concentrator type |
US20040079408A1 (en) * | 2002-10-23 | 2004-04-29 | The Boeing Company | Isoelectronic surfactant suppression of threading dislocations in metamorphic epitaxial layers |
Cited By (73)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8998919B2 (en) | 2003-06-25 | 2015-04-07 | DePuy Synthes Products, LLC | Assembly tool for modular implants, kit and associated method |
US20050033444A1 (en) * | 2003-06-25 | 2005-02-10 | Jones Michael C. | Assembly tool for modular implants and associated method |
US20040267373A1 (en) * | 2003-06-25 | 2004-12-30 | Dwyer Kimberly Ann | Assembly tool for modular implants and associated method |
US8419799B2 (en) | 2003-06-25 | 2013-04-16 | Depuy Products, Inc. | Assembly tool for modular implants and associated method |
US9381097B2 (en) | 2003-06-25 | 2016-07-05 | DePuy Synthes Products, Inc. | Assembly tool for modular implants, kit and associated method |
US8685036B2 (en) | 2003-06-25 | 2014-04-01 | Michael C. Jones | Assembly tool for modular implants and associated method |
US9584065B2 (en) * | 2007-08-17 | 2017-02-28 | Basf Se | Solar cell structure |
US20150144192A1 (en) * | 2007-08-17 | 2015-05-28 | Basf Se | Solar cell structure |
US9717545B2 (en) | 2007-10-30 | 2017-08-01 | DePuy Synthes Products, Inc. | Taper disengagement tool |
US9119601B2 (en) | 2007-10-31 | 2015-09-01 | DePuy Synthes Products, Inc. | Modular taper assembly device |
US8518050B2 (en) | 2007-10-31 | 2013-08-27 | DePuy Synthes Products, LLC | Modular taper assembly device |
US20090250099A1 (en) * | 2008-04-07 | 2009-10-08 | Eric Ting-Shan Pan | Solar-To-Electricity Conversion System Using Cascaded Architecture of Photovoltaic and Thermoelectric Devices |
US20090250098A1 (en) * | 2008-04-07 | 2009-10-08 | Eric Ting-Shan Pan | Method for Solar-To-Electricity Conversion |
US20090250097A1 (en) * | 2008-04-07 | 2009-10-08 | Eric Ting-Shan Pan | Solar-To-Electricity Conversion System |
US20090250096A1 (en) * | 2008-04-07 | 2009-10-08 | Eric Ting-Shan Pan | Solar-To-Electricity Conversion Sub-Module |
US20100218807A1 (en) * | 2009-02-27 | 2010-09-02 | Skywatch Energy, Inc. | 1-dimensional concentrated photovoltaic systems |
US20110036345A1 (en) * | 2009-05-26 | 2011-02-17 | Cogenra Solar, Inc. | Concentrating Solar Photovoltaic-Thermal System |
US20100319684A1 (en) * | 2009-05-26 | 2010-12-23 | Cogenra Solar, Inc. | Concentrating Solar Photovoltaic-Thermal System |
US20110114154A1 (en) * | 2009-11-19 | 2011-05-19 | Cogenra Solar, Inc. | Receiver for concentrating photovoltaic-thermal system |
US20110017267A1 (en) * | 2009-11-19 | 2011-01-27 | Joseph Isaac Lichy | Receiver for concentrating photovoltaic-thermal system |
US10312392B2 (en) * | 2010-03-29 | 2019-06-04 | Airbus Defence and Space GmbH | Multi-junction solar cell for space applications |
US20110232733A1 (en) * | 2010-03-29 | 2011-09-29 | Astrium Gmbh | Multi-Junction Solar Cell For Space Applications |
US9353973B2 (en) | 2010-05-05 | 2016-05-31 | Sunpower Corporation | Concentrating photovoltaic-thermal solar energy collector |
US8686279B2 (en) | 2010-05-17 | 2014-04-01 | Cogenra Solar, Inc. | Concentrating solar energy collector |
US8669462B2 (en) | 2010-05-24 | 2014-03-11 | Cogenra Solar, Inc. | Concentrating solar energy collector |
US8852994B2 (en) | 2010-05-24 | 2014-10-07 | Masimo Semiconductor, Inc. | Method of fabricating bifacial tandem solar cells |
US9368671B2 (en) | 2010-05-24 | 2016-06-14 | Masimo Semiconductor, Inc. | Bifacial tandem solar cells |
US9101495B2 (en) | 2010-06-15 | 2015-08-11 | DePuy Synthes Products, Inc. | Spiral assembly tool |
US10166118B2 (en) | 2010-06-15 | 2019-01-01 | DePuy Synthes Products, Inc. | Spiral assembly tool |
US9095452B2 (en) | 2010-09-01 | 2015-08-04 | DePuy Synthes Products, Inc. | Disassembly tool |
US9867720B2 (en) | 2010-09-01 | 2018-01-16 | DePuy Synthes Products, Inc. | Disassembly tool |
US10292837B2 (en) | 2010-09-01 | 2019-05-21 | Depuy Synthes Products Inc. | Disassembly tool |
WO2013106000A1 (en) * | 2011-02-16 | 2013-07-18 | Caelux Corporation | Wire array solar cells employing multiple junctions |
US9597188B2 (en) | 2011-04-06 | 2017-03-21 | DePuy Synthes Products, Inc. | Version-replicating instrument and orthopaedic surgical procedure for using the same to implant a revision hip prosthesis |
US10226345B2 (en) | 2011-04-06 | 2019-03-12 | DePuy Synthes Products, Inc. | Version-replicating instrument and orthopaedic surgical procedure for using the same to implant a revision hip prosthesis |
US9504578B2 (en) | 2011-04-06 | 2016-11-29 | Depuy Synthes Products, Inc | Revision hip prosthesis having an implantable distal stem component |
US10925739B2 (en) | 2011-04-06 | 2021-02-23 | DePuy Synthes Products, Inc. | Version-replicating instrument and orthopaedic surgical procedure for using the same to implant a revision hip prosthesis |
US9737405B2 (en) | 2011-04-06 | 2017-08-22 | DePuy Synthes Products, Inc. | Orthopaedic surgical procedure for implanting a revision hip prosthesis |
US10888427B2 (en) | 2011-04-06 | 2021-01-12 | DePuy Synthes Products, Inc. | Distal reamer for use during an orthopaedic surgical procedure to implant a revision hip prosthesis |
US10772730B2 (en) | 2011-04-06 | 2020-09-15 | DePuy Synthes Products, Inc. | Finishing rasp and orthopaedic surgical procedure for using the same to implant a revision hip prosthesis |
US10603173B2 (en) | 2011-04-06 | 2020-03-31 | DePuy Synthes Products, Inc. | Orthopaedic surgical procedure for implanting a revision hip prosthesis |
US9949833B2 (en) | 2011-04-06 | 2018-04-24 | DePuy Synthes Products, Inc. | Finishing RASP and orthopaedic surgical procedure for using the same to implant a revision hip prosthesis |
US10064725B2 (en) | 2011-04-06 | 2018-09-04 | DePuy Synthes Products, Inc. | Distal reamer for use during an orthopaedic surgical procedure to implant a revision hip prosthesis |
US20130056053A1 (en) * | 2011-09-02 | 2013-03-07 | Amberwave Inc. | Solar cell |
US10879414B2 (en) * | 2012-09-14 | 2020-12-29 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US20150333208A1 (en) * | 2012-09-14 | 2015-11-19 | The Boeing Company | GROUP-IV SOLAR CELL STRUCTURE USING GROUP-IV or III-V HETEROSTRUCTURES |
US12068426B2 (en) | 2012-09-14 | 2024-08-20 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US20140076388A1 (en) * | 2012-09-14 | 2014-03-20 | The Boeing Company | GROUP-IV SOLAR CELL STRUCTURE USING GROUP-IV or III-V HETEROSTRUCTURES |
US11133429B2 (en) | 2012-09-14 | 2021-09-28 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US20180190850A1 (en) * | 2012-09-14 | 2018-07-05 | The Boeing Company | GROUP-IV SOLAR CELL STRUCTURE USING GROUP-IV or III-V HETEROSTRUCTURES |
US11646388B2 (en) | 2012-09-14 | 2023-05-09 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US9947823B2 (en) | 2012-09-14 | 2018-04-17 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US10998462B2 (en) * | 2012-09-14 | 2021-05-04 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US9099595B2 (en) * | 2012-09-14 | 2015-08-04 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US10811553B2 (en) | 2012-09-14 | 2020-10-20 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US11495705B2 (en) | 2012-09-14 | 2022-11-08 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US12080820B2 (en) | 2012-09-14 | 2024-09-03 | The Boeing Company | Group-IV solar cell structure using group-IV heterostructures |
US10896990B2 (en) | 2012-09-14 | 2021-01-19 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US10903383B2 (en) | 2012-09-14 | 2021-01-26 | The Boeing Company | Group-IV solar cell structure using group-IV or III-V heterostructures |
US11595000B2 (en) | 2012-11-08 | 2023-02-28 | Maxeon Solar Pte. Ltd. | High efficiency configuration for solar cell string |
US9270225B2 (en) | 2013-01-14 | 2016-02-23 | Sunpower Corporation | Concentrating solar energy collector |
US9530921B2 (en) | 2014-10-02 | 2016-12-27 | International Business Machines Corporation | Multi-junction solar cell |
US10580926B2 (en) | 2014-10-02 | 2020-03-03 | International Business Machines Corporation | Multi-junction solar cell |
US10312400B2 (en) | 2014-10-02 | 2019-06-04 | International Business Machines Corporation | Multi-junction solar cell |
US10749053B2 (en) * | 2017-03-03 | 2020-08-18 | Solaero Technologies Corp. | Distributed Bragg reflector structures in multijunction solar cells |
US11282979B2 (en) * | 2017-03-03 | 2022-03-22 | Solaero Technologies Corp. | Distributed bragg reflector structures in multijunction solar cells |
US20180254357A1 (en) * | 2017-03-03 | 2018-09-06 | Solaero Technologies Corp. | Distributed bragg reflector structures in multijunction solar cells |
US11245046B2 (en) * | 2017-04-17 | 2022-02-08 | Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences | Multi-junction tandem laser photovoltaic cell and manufacturing method thereof |
CN107195712A (en) * | 2017-06-12 | 2017-09-22 | 广东爱康太阳能科技有限公司 | A kind of silicon class binode lamination solar cell |
US20220020890A1 (en) * | 2019-06-03 | 2022-01-20 | Suzhou Institute Of Nano-Tech And Nano-Bionics (Sinano), Chinese Academy Of Sciences | Multi-junction laminated laser photovoltaic cell |
US11611008B2 (en) * | 2019-06-03 | 2023-03-21 | Suzhou Institute Of Nano-Tech And Nano-Bionics (Sinano), Chinese Academy Of Sciences | Multi-junction laminated laser photovoltaic cell |
US12107182B2 (en) | 2020-10-19 | 2024-10-01 | The Boeing Company | Group-IV solar cell structure using group-IV heterostructures |
CN113206164A (en) * | 2021-04-26 | 2021-08-03 | 宜兴市昱元能源装备技术开发有限公司 | Cast tandem multi-junction photovoltaic cell |
Also Published As
Publication number | Publication date |
---|---|
WO2005020334A3 (en) | 2005-06-30 |
WO2005020334A2 (en) | 2005-03-03 |
WO2005020334A9 (en) | 2007-03-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20050081910A1 (en) | High efficiency tandem solar cells on silicon substrates using ultra thin germanium buffer layers | |
Yamaguchi et al. | Multi-junction solar cells paving the way for super high-efficiency | |
US9293615B2 (en) | Low-bandgap, monolithic, multi-bandgap, optoelectronic devices | |
Dimroth | High‐efficiency solar cells from III‐V compound semiconductors | |
US6340788B1 (en) | Multijunction photovoltaic cells and panels using a silicon or silicon-germanium active substrate cell for space and terrestrial applications | |
US9287431B2 (en) | Superstrate sub-cell voltage-matched multijunction solar cells | |
US8067687B2 (en) | High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters | |
Dimroth et al. | High-efficiency multijunction solar cells | |
US9276156B2 (en) | Solar cells having a transparent composition-graded buffer layer | |
CA2340997C (en) | Multijunction photovoltaic cell with thin 1st (top) subcell and thick 2nd subcell of same or similar semiconductor material | |
Wanlass et al. | Lattice-mismatched approaches for high-performance, III-V photovoltaic energy converters | |
CN102227816B (en) | Photovoltaic cell | |
US20060162767A1 (en) | Multi-junction, monolithic solar cell with active silicon substrate | |
US20100269895A1 (en) | Multijunction photovoltaic structure with three-dimensional subcell | |
Wanlass et al. | High-performance, 0.6-eV, Ga 0.32 In 0.68 As/InAs 0.32 P 0.68 thermophotovoltaic converters and monolithically interconnected modules | |
Yamaguchi et al. | Overview of Si tandem solar cells and approaches to PV-powered vehicle applications | |
WO2003100868A1 (en) | Low-bandgap, monolithic, multi-bandgap, optoelectronic devices | |
Wanlass et al. | GaInP/GaAs/GaInAs monolithic tandem cells for high-performance solar concentrators | |
Wehrer et al. | InGaAs series-connected, tandem, MIM TPV converters | |
JP5548908B2 (en) | Manufacturing method of multi-junction solar cell | |
Ringel et al. | Multi-junction III-V photovoltaics on lattice-engineered Si substrates | |
US20140069493A1 (en) | Photovoltaic device | |
Wanlass et al. | Recent Advances in Low‐Bandgap, InP‐Based GaInAs/InAsP Materials and Devices for Thermophotovoltaic (TPV) Energy Conversion | |
Mathews et al. | Mechanically stacked solar cells for concentrator photovoltaics | |
TWI383509B (en) | A method of stacking solar cells |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MASSACHUSETTS INSTITUTE OF TECHNOLOGY, MASSACHUSET Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SPARACIN, DANIEL K.;GRAHAM, JEREMY;WADA, KAZUMI;AND OTHERS;REEL/FRAME:016090/0907;SIGNING DATES FROM 20041123 TO 20041216 |
|
AS | Assignment |
Owner name: MASSACHUSETTS INSTITUTE OF TECHNOLOGY, MASSACHUSET Free format text: RE-RECORD TO CORRECT THE NAME OF THE FIRST ASSIGNOR, PREVIOUSLY RECORDED ON REEL 016090 FRAME 0907.;ASSIGNORS:DANIELSON, DAVID T.;GRAHAM, JEREMY;WADA, KAZUMI;AND OTHERS;REEL/FRAME:016691/0254;SIGNING DATES FROM 20041123 TO 20041216 |
|
AS | Assignment |
Owner name: NATIONAL SCIENCE FOUNDATION, VIRGINIA Free format text: CONFIRMATORY LICENSE;ASSIGNOR:MASSACHUSETTS INSTITUTE OF TECHNOLOGY;REEL/FRAME:019599/0001 Effective date: 20040915 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |